Search Previous Year Questions

The correct answer is CO2, N2O.

Explanation:

Greenhouse gas: 

• The gases which allow solar radiation to pass through them but retain and partially reflect back radiation of longer wavelength are called greenhouse gases.
• Examples of greenhouse gases are carbon dioxide (CO₂), methane (CH₄), Chlorofluorocarbon, nitrous oxide (N₂O), ozone (O₃).
• These gases are required to keep the earth warm and hospitable.
• They prevent a significant portion of the long-wave radiation emitted by earth from escaping into space.
• Instead, greenhouse gases reflect some of this energy back to the earth.
• These gases are responsible for the greenhouse effect.
• Carbon dioxide (CO₂₎ is the most abundant (60 percent) among greenhouse gases.

Thus, the pair of greenhouse gases is CO2, N2O.

Additional Information

Nitrogen (N₂):

• Nitrogen is not a greenhouse gas because it does not absorb infrared radiation and therefore does not trap heat in the atmosphere.

Oxygen (O₂):

• Oxygen is not a greenhouse gas because they do not absorb infrared radiation.

The correct answer is Television.

Concept:

• A teaching aid is anything that a teacher uses to help teach or make a lesson more interesting for students.
• Teaching aids come in any form.
• Pictures, videos, charts, flashcards, and objects such as three-dimensional models or educational toys are the most common.

 Key Points

Audio aids:

• Audio aids are materials or devices that use the auditory senses to help people learn by listening, such as radio broadcasts, cassette players, and CD players.

Visual aids:

• These are aids that use the visual senses to help learners learn by viewing.
• Important examples include Blackboard, Charts, Pictures, Graphs, Models, Film Strips, Slides, etc.

Audio-Visual Aids:

• Devices that require both the auditory and visual senses and assist students in learning by listening and viewing.
• Television, films, and computer-assisted instruction are examples of such aids.

The correct answer is Rhizobium.

Concept:

• Microorganisms are too small and are not visible to naked eyes.
• Microorganisms are found in air, water and in the bodies of plants and animals.
• They may be unicellular or multicellular.
• Microorganisms are classified into four major groups.
• Bacteria- Bacteria convert gaseous nitrogen into a usable form and release it into the soil.
• Fungi- Fungi are cosmopolitan and occur in air, water, soil and on animals and plants.
• Protozoa- protozoans are heterotrophs and live as predators or parasites.
• Algae- Algae are largely aquatic both fresh water and marine organisms.

Explanation:

• Leguminous plants belong to the family Fabaceae.
• These plants have a symbiotic relationship with the soil bacteria Rhizobium, which lives in their roots.
• Rhizobium is a biofertiliser.
• Biofertilizers are the microorganisms that enrich the nutrient (nitrogen, phosphorous, etc.) quality of the soil.
• Rhizobium is a symbiotic bacterium that lives in the root nodules of leguminous plants and fixes atmospheric nitrogen into organic compound (ammonia) and it also fertilizes the soil.
• It causes the formation of special structures known as nodules within the cell, which fix atmospheric nitrogen.
• It accomplishes this with the help of the nitrogenase enzyme, which converts nitrogen to ammonium, a necessary factor for plant growth.
• Rhizobium bacteria form symbiotic associations with plants.
• Plants provide them with food and shelter, and these bacteria fix nitrogen in the soil.

The correct answer is Potato.

Concept:

The Stem: 

• Stem is the aerial part of the plant and develops from the plumule of the embryo of a germinating seed.
• It bears nodes and internodes, where node is the region from where leaves are born and internodes are the region between two nodes.

Modifications of Stem:

• In some plants, the stems are modified to perform the function of storage of food, support, protection, and vegetative propagation.

Explanation:

• Potato tuber is a modified stem or the edible part of the potato.
• The stem is not always what it appears to be.
• They are modified to perform a variety of functions such as food storage, penetration organs, etc.
• The various modifications of stems are tuber, stolon, bulb, corm, and rhizome.
• A tuber is a thickened underground part of a stem.
• It has buds that can produce a new plant through vegetative propagation.
• A tuber contains a large amount of edible starch which is used as food.

The correct answer is Sclerenchyma.

Concept:

• A tissue is a group of cells having common origin and usually performing a common function.
• They form a cellular organizational level, intermediate between the cells and organ system.
• Organs are then created by combining the functional groups of tissues.
• The plant body is made up of different kinds of tissues.
• The plant tissues can be divided into two main types:
• Meristematic tissue
• Permanent tissue

Explanation:

Permanent tissue:

• The meristematic cells gradually differentiate and loose the ability to divide. Such cells are termed as mature of permanent cells.
• The permanent tissues actually composed of cells in which the growth has stopped.
• Permanent tissues can be divided into two types.
• Simple tissue – parenchyma, collenchyma, and sclerenchyma
• Complex tissue – xylem and phloem
• Simple tissue:
• The permanent tissue having all cells similar in structure and function are called simple tissues.
• Parenchyma:
• It is a living, simple permanent tissue composed of thin-walled cells.
• Parenchyma is also called primary tissue or ground tissue.
• It is present in cortex, pith, palisade, mesophyll and some other parts of the flower.
• It is mostly produced by the ground tissue. The parenchyma forms the major part of the plant organs.
• Collenchyma:
• Collenchyma is a simple, living mechanical tissue.
• Its cells are composed of more or less elongated cells with thick, primary non-lignified walls.
• Intercellular spaces are found to be absent.
• Sclerenchyma: 
• The sclerenchyma consists of long, narrow cells with thick and lignified cell walls having a few or numerous pits.
• These are dead cells and do not perform any metabolic function.
• It provides mechanical strength and support.

The correct answer is Oxygen.

Concept:

• Air pollutants cause air pollution.
• Any undesirable change in the physical, chemical and biological characteristics of air that exert adverse effects on human beings is defined as air pollution.
• Air pollutants are the harmful substances found in the atmosphere that harm the ecological system.
• There are two types of air pollutants:
• Gaseous air pollutants: These are oxides of sulphur, nitrogen and carbon, hydrogen sulphide, hydrocarbons, ozone and other oxidants.
• Particulate pollutants: These are dust, mist, fumes, smoke, smog, etc.
• Major air pollutants are carbon mono-oxide, sulphur dioxide, nitrogen oxide, fly ash, methane, suspended particulate
• matter, etc.

Explanation:

Oxygen:

• Oxygen (O₂) is not an air pollutant as the atmospheric composition contains 78 percent nitrogen and 21 percent oxygen by proportion.

Carbon monoxide: 

• Carbon monoxide (CO) is one of the most serious air pollutants.
• It is a colourless and odourless gas, highly poisonous to living beings because of its ability to block the delivery of oxygen to the organs and tissues.

Methane:

• Methane (CH₄) is a harmful air pollutant and greenhouse gas that causes one million premature deaths each year.
• Methane is another potent greenhouse gas. It is 80 times more potent than carbon dioxide at warming over a 20-year period.

Nitrogen oxide:

• Nitrogen oxides (NO) have long been recognized as toxic environmental pollutants.

Thus, Oxygen is not an air pollutant.

The correct answer is Option 4.

Concept:

Biodiversity:

• The occurrence of different types of genes, gene pools, species, habitats and ecosystems in a particular place and various parts of earth is called biodiversity.
• Biodiversity can be conserved by protecting its whole ecosystem.
• There are two basic approaches for the conservation of biodiversity.
• In-situ conservation (On-site conservation)
• This approach involves the protection of species in their natural habitat.
• Ex-situ conservation (Off-site conservation)
• This approach involves placing threatened animals and plants in special care units for their protection.

Explanation:

• Sacred groves are the forest patches set aside for worship.
• These are also called sacred woods.
• Sacred groves are examples of in-situ conservation of biodiversity.
• All the trees and wildlife within are given total protection by tribal people.
• Some of the sacred groves in India are as follows:
• Khansi and Jaintia Hills in Meghalaya
• Western Ghat regions of Karnataka and Maharashtra
• Aravalli Hills of Rajasthan
• Sarguja, Chanda and Bastar areas of Madhya Pradesh
• Sacred groves in Meghalaya represent a long tradition of environmental conservation by tribal communities based on indigenous knowledge.
• The general term for sacred groves in the Khasi Hills is 'Khlaw Kyntang' or 'Law Kyntang' or 'Law Lyngdoh' while in the Jaintia Hills it is called 'Khloo Blai'.

The correct answer is Streptococcus pneumonia.

Explanation:

• Pleurisy is an inflammation of the pleura, which is two large, thin layers of tissue that separate your lungs from your chest wall.
• Pleurisy, also known as pleuritis, causes sharp chest pain (pleuritic pain) that worsens with breathing.
• Pleurisy is caused by the Streptococcus pneumonia bacteria.
• Pleurisy can affect people of all ages, but those 65 and older are more at risk because they are more likely to develop a chest infection.
• Signs and symptoms of pleurisy:
• Cough
• Fatigue extreme tiredness)
• Fever
• Shortness of breath
• Unexplained weight loss
• Treatment for pleurisy
• Treatment for pleurisy may include:
• Pleurisy treatment may include: treating the underlying cause - for example, tuberculosis treatment anti-inflammatory medications
• other medications to manage the pain
• antibiotics used to treat a bacterial infection
• in the case of a pleural effusion, draining the excess fluid

Additional Information

Mycobacterium tuberculosis

• Mycobacterium tuberculosis bacterium causes Tuberculosis (TB).
• It is spread when a person with active tuberculosis in their lungs coughs or sneezes and someone else inhales the TB bacteria-containing expelled droplets.
• Although tuberculosis is spread in a manner similar to a cold or flu, it is not as contagious.

Corynebacterium diphtheriae:

• Diphtheria is a serious infection caused by bacteria strains called Corynebacterium diphtheriae, which produce a toxin (poison). It is the toxin that can make people very ill.
• Diphtheria bacteria spread from person to person, most commonly via respiratory droplets such as coughing or sneezing.
• Touching infected open sores or ulcers can also make people sick.

Mycobacterium leprae:

• Mycobacterium leprae causes leprosy, also known as Hansen's disease, which is a chronic infectious disease.
• The disease primarily affects the skin, peripheral nerves, upper respiratory tract mucosal surfaces, and the eyes.
• Leprosy is known to affect people of all ages, from infancy to old age.
• Leprosy is curable, and early treatment can prevent disability.

The correct answer is Holocrine.

Explanation

• The human skin has a variety of exocrine glands that secrete biochemical products onto the skin's surface.
• A sebaceous gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete sebum, an oily or waxy matter that lubricates mammals' hair and skin.
• Holocrine type of sebaceous glands present in human skin.
• Sebaceous glands are most abundant on the face and scalp, but they can be found on any part of the skin except the palms of the hands and soles of the feet.
• The sebaceous glands in the skin can eliminate certain substances through their secretions.
• Sebum from sebaceous glands eliminates sterols, fatty acids, waxes and hydrocarbons.
• This secretion is mainly meant for a protective oily covering of the skin.

Additional Information

• Sweat glands (both eccrine and apocrine ones) are merocrine glands.
• The secretion of sweat glands (sweat) is an aqueous fluid containing NaCl, lactic acid, small amounts of urea, amino acids and glucose.
• Control of sweat lost is an example of homeostasis control, for regulating the body temperature (i.e., to facilitate a cooling effect on the body surface).

The correct answer is Night-blindness.

Concept:

• Vitamins are organic substances that are needed in sufficient quantities to maintain good health.
• Natural sources of vitamins are fruits and vegetables.
• Our body, however, cannot synthesize them. Therefore, we need to consume natural sources such as fruits and vegetables.
• Vitamins are divided into two groups water-soluble vitamins (Vitamins of B group and Vitamin C) and fat-soluble vitamins (Vitamins A, D, E, and K).​
• Each vitamin has a specific function and its deficiency leads to a particular deficiency disease.

Explanation:

• Night-blindness is caused by a deficiency of Vitamin A.
• Night blindness, also known as nyctalopia, is a lack of proper vision at night. It can also happen in dim light.
• Natural cures for night blindness include eating vitamin A-rich foods such as green leafy vegetables, fish, and dairy products.
• Night blindness worsens with age as they allow less light to pass through.
• Vitamin A, also known as retinol, helps in the conversion of nerve impulses into images in the retina.
• In the back of your eye, there is a light-sensitive area called the retina.

Additional Information

List of Vitamins and their functions: